1. Field of the Invention
The present invention relates generally to a modular fluid handling assembly for conducting or distributing one or more fluids, and the individual modular fluid handling units comprising the assembly. More particularly, the invention relates to a modular fluid handling assembly, and individual units, with double-containment sealing capability. The invention further relates to a modular fluid handling assembly, and individual units, which allow for continuous monitoring of, and drawing off of, fluid leakage.
2. Description of the Related Art
In the semiconductor manufacturing industry, many hazardous fluids are used and must be carefully handled to prevent damage to equipment and injury to both the environment and production employees. Examples of such fluids include toxic and corrosive gases such as SiH.sub.4, BCl.sub.3, and HCl. These fluids must be kept as pure as possible during all aspects of the handling and supply, since any contact of the flow stream with a contaminant may result in defects in the manufactured products. These defects are usually not detected until after the manufacturing operation has been completed.
During the manufacturing process, certain fluids must be distributed to various locations in precise amounts. To accomplish this, the industry has used gas sticks, which comprise a plurality of discrete blocks connected together, and on which a plurality of external devices may be mounted. FIGS. 6a-6c depict one such conventional block.
The conventional block 90 includes a fluid passage 91, and associated ports 92, 92', through which a process fluid flows. The block 90 also includes external device passages 93, 94 and associated ports 95, 95', 96, 96', for fluid communication with an external device 97. When two or more blocks 90 are connected together, the process fluid flows through and among the blocks 90 and one or more external devices 97 by way of the internally bored passages 91, 93, 94 and associated ports 92, 92', 95, 95', 96, 96'. These discrete blocks 90 and external devices 97 require numerous junctions, which result in numerous opportunities for leakage.
To alleviate leakage between and among the discrete blocks 90 and external devices 97, the industry has used metallic compression seals 98 at junctions between the individual passage ports 92, 92', 95, 95', 96, 96'. However, these individual seals 98 are still subject to leakage. Even extremely small amounts of leakage can result in personnel injury, equipment damage, or manufacturing defects. Typically, these leaks are detected only by detecting product degradation or by removing the entire gas stick from the system and performing a conventional leak test.